It is known to provide motor vehicles with a launch control system for launching the vehicle from a stationary position. The launch control system typically controls speed of an internal combustion engine and transmission upshifts, for example through a dual-clutch transmission. The launch control system is activated, for example by pressing a launch control button and selecting a sport operating mode for the vehicle. The toot brake is then applied to hold the vehicle stationary and the throttle pedal is depressed. The throttle pedal, is typically depressed to a kickdown position to increase the engine speed. The launch control system controls the engine speed, for example at a constant 4000 rmp, but the engine speed could be higher or lower. The driver then rapidly releases the brake pedal allowing the vehicle to accelerate. The traction control system can subsequently control engine speed to reduce or minimise wheelspin and control transmission upshifts as the vehicle speed increases. The clutch pressure can be controlled to allow slip to occur between friction surfaces to control the delivery of torque.
The torque demand resulting from depressing the throttle pedal to the kickdown position places a high load on the engine. The subsequent engagement of the transmission at high engine speed can provide a considerable mechanical load, for example causing heating and wear of the transmission clutches. Moreover, this launch strategy may not be suitable for vehicles having a torque converter which provides a fluid coupling for an automatic transmission. For example, unlike a dual-clutch transmission, it is not possible with a torque converter to control torque delivery by varying the clutch pressure.
The present invention, at least in certain embodiments, sets out to overcome or ameliorate some of the aforementioned shortcomings of prior art launch control units.